Method for manufacturing bleached pulp, feedstock, and packaging system

ABSTRACT

A feedstock includes feedstock paper and non-paper material. The feedstock paper includes lignin and cellulose. A method includes cooking the feedstock in cooking liquor to dissolve at least a portion of the lignin from the feedstock paper and to at least partially dissolve the non-paper material in the cooking liquor, thereby yielding a cooked pulp. The method further includes washing the cooked pulp to yield washed pulp and spent cooking liquor, regenerating the spent cooking liquor to yield regenerated cooking liquor, and bleaching the washed pulp.

PRIORITY

This application claims priority from U.S. Ser. No. 63/151,981 filed on Feb. 22, 2021, the entire contents of which are incorporated herein by reference.

FIELD

The present application relates to the manufacture of pulp from feedstock paper, and, in particular, manufacturing pulp from OCC materials.

BACKGROUND

A substantial portion of bleached pulp is manufactured by bleaching of virgin pulp obtained by chemical pulping of wood chips. Bleached chemical pulp is used to manufacture various paper products, which are used in a wide variety of applications. For example, paperboard manufactured from bleached chemical pulp is commonly used for various packaging applications, such as packaging for food (e.g., cartons) and packaging for beverages (e.g., cups). There is a growing interest in bleached paper products manufactured from recycled pulp. Recycled pulp suitable for manufacturing of bleached paper products may be obtained from repulping of bleached paper products.

Recycled pulp is recovered from unbleached paper products or mixtures of bleached or unbleached paper products, such as old corrugated containers (OCC) materials. Traditionally, OCC materials are delivered to paper processors where they are processed using traditional OCC recycling processes to yield free fibers, which are processed into different paper products such as recycled paperboard, the center fluting of corrugated boxes, and as unbleached kraft paperboard. The continued growth of e-commerce has resulted in more home deliveries in corrugated containers, and, thus, increased generation of OCC materials.

Traditional recycling of OCC materials is straightforward if non-paper material is removed from the OCC materials prior to collection. If not, then traditional recycling of OCC materials requires screening and removal of non-paper material prior to the traditional OCC recycling processes. The screening and removal of non-paper material increases the difficulty of traditional OCC recycling. Meanwhile, the removed non-paper material is often burned or landfilled.

With industry sustainability goals moving towards the circular economy, there is a desire to deliver more complete recyclability of OCC materials and an upcycled purpose for the pulp recovered from OCC materials.

Accordingly, those skilled in the art continue with research and development in the field of manufacturing pulp from paper products, and, in particular, manufacturing pulp from OCC materials.

SUMMARY

In one embodiment, a method for manufacturing bleached pulp from a feedstock including feedstock paper and non-paper material, in which the feedstock paper includes lignin and cellulose, includes: cooking the feedstock in cooking liquor to dissolve at least a portion of the lignin from the feedstock paper and to at least partially dissolve the non-paper material in the cooking liquor, thereby yielding a cooked pulp; washing the cooked pulp to yield washed pulp and spent cooking liquor; regenerating the spent cooking liquor to yield regenerated cooking liquor; and bleaching the washed pulp.

In another embodiment, a method for manufacturing bleached pulp from a feedstock including feedstock paper and non-paper material, in which the feedstock paper includes lignin and cellulose, includes: cooking the feedstock in cooking liquor to dissolve at least a portion of the lignin from the feedstock paper and to substantially fully dissolve the non-paper material in the cooking liquor, thereby yielding a cooked pulp; washing the cooked pulp to yield washed pulp and spent cooking liquor; regenerating the spent cooking liquor to yield regenerated cooking liquor; and bleaching the washed pulp.

In another embodiment, a feedstock for manufacturing bleached pulp includes feedstock paper and non-paper material intermixed with the feedstock paper. The non-paper material is capable of dissolving, at least partially, in a cooking liquor.

In another embodiment, a feedstock for manufacturing bleached pulp includes feedstock paper and non-paper material intermixed with the feedstock paper. The non-paper material is capable of substantially fully dissolving in a cooking liquor.

In another embodiment, a packaging system includes a corrugated package and a non-paper packaging material capable of dissolving, at least partially, in a cooking liquor.

In yet another embodiment, a packaging system includes a corrugated package and a non-paper packaging material capable of substantially fully dissolving in a cooking liquor.

Other embodiments of the disclosed methods, feedstock, and packaging systems will become apparent from the following detailed description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary method of manufacturing of manufacturing bleached pulp according to an aspect of the present description.

FIG. 2 is a schematic illustration of a packaging system according to an aspect of the present description, in an unsealed state.

FIG. 3 is a schematic illustration of the packaging system of FIG. 2 in a sealed state.

DETAILED DESCRIPTION

A recent solution has been found to provide an economical process for converting feedstock paper, and, in particular, OCC materials, to bleached recycled pulp. However, the reality of current OCC materials is that the OCC materials typically contain non-paper material. The presence of non-paper material creates challenges with regards to separation of the non-paper material prior to the conversion process. The feedstock of the present description can bypass the traditional OCC plant and go straight to the pulping process to recover bleachable fiber. Thus, by selecting the right materials for the feedstock, and a packaging system to be eventually used as feedstock, the present description can avoid large investments in OCC separation technology.

FIG. 1 is an exemplary method of manufacturing of manufacturing bleached pulp according to an aspect of the present description.

The present disclosure relates to a novel feedstock 10 comprising feedstock paper 11 and non-paper material 12 intermixed with the feedstock paper 11, wherein the non-paper material 12 is capable of dissolving, at least partially, if not substantially fully, in a cooking liquor. As used herein, the term “paper” refers to any material formed from pressed/laid fibers of cellulosic pulp and includes paperboard.

The feedstock paper 11 includes lignin 13 and cellulose 14. The feedstock paper 11 may have a relatively high quantity of lignin 13. In one expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 60. In another expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 70. In another expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 80. In another expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 90. In yet another expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 100. In yet another expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 110. In yet another expression, a feedstock paper 11 useful in the disclosed methods may have, on average, a kappa number of at least 120.

The non-paper material 12 includes any non-paper material 12 capable of dissolving, at least partially, in a cooking liquor, which is a chemical solution employed to reduce wood chips (or, in the case of the present disclosure, feedstock paper) into cellulose fiber by dissolving lignin. In one particular implementation, the cooking liquor may be a kraft cooking liquor, and may include sodium hydroxide (NaOH) and sodium sulfide (Na₂S) among other possible components. In other particular implementations, the cooking liquor may use other types of cooking chemistries (soda, sulfite, green liquor, and carbonate).

In one expression, the non-paper material 12 is capable of substantially fully dissolving in the cooking liquor. For example, the non-paper material 12 may be about 100 percent soluble in the cooking liquor.

In another expression, the non-paper material 12 at least partially dissolves in the cooking liquor. In one example, the non-paper material 12 may be at least 50 percent (by weight) soluble in the cooking liquor. In another example, the non-paper material 12 may be at least 60 percent (by weight) soluble in the cooking liquor. In another example, the non-paper material 12 may be at least 70 percent (by weight) soluble in the cooking liquor. In another example, the non-paper material 12 may be at least 80 percent (by weight) soluble in the cooking liquor. In another example, the non-paper material 12 may be at least 85 percent (by weight) soluble in the cooking liquor. In another example, the non-paper material 12 may be at least 90 percent (by weight) soluble in the cooking liquor. In another example, the non-paper material 12 may be at least 95 percent (by weight) soluble in the cooking liquor. In yet another example, the non-paper material 12 may be at least 98 percent (by weight) soluble in the cooking liquor.

In an aspect, the non-paper material 12 has a positive gross heating value in the dissolved state when dissolved within the cooking liquor. By having a positive heating value in the dissolved state when dissolved within the cooking liquor, the non-paper material 12 contributes to a regeneration process for regenerating a spent cooking liquor 30 to yield regenerated cooking liquor 20 using the positive heating value of the non-paper material 12. The heating value in the dissolved state may be determined by comparing a heating value of a spent cooking liquor 20 with the dissolved non-paper material 12 with a heating value of a spent cooking liquor 20 without the dissolved non-paper material 12. If the heating value of the spent cooking liquor 20 with the dissolved non-paper material 12 is greater than the heating value of a spent cooking liquor 20 without the dissolved non-paper material 12, then the non-paper material 12 has a positive gross heating value in the dissolved state when dissolved within the cooking liquor. In one particular implementation, the non-paper material 12 has a high positive gross heating value in the dissolved state when dissolved within the cooking liquor. As one example, the non-paper material 12 may increase the heating value of the spent cooking liquor by at least 0.01 kJ per gram of the solid content of the non-paper material 12. In another example, the non-paper material 12 may increase the heating value of the spent cooking liquor by at least 0.1 kJ/g.

In yet another implementation, the non-paper material 12 may increase the heating value of the spent cooking liquor by at least 1 kJ/g. In yet another implementation, the non-paper material 12 may increase the heating value of the spent cooking liquor by at least 10 kJ/g.

Exemplary suitable non-paper material 12 capable of dissolving, at least partially, in the cooking liquor includes organic or inorganic non-paper material 12 capable of dissolving in the cooking liquor. Suitable non-paper material 12 may include, for example, acrylic, ethylene vinyl acetate, epoxy resins, fiberglass, isocyanate, isoprene, polyethylene glycol, polyethylene oxide, polyvinyl acetate, polyvinyl chloride, propionates, silicone, starch, stearic acid monoglycerides, and styrene acrylic.

In one particular implementation, the non-paper material 12 capable of dissolving, at least partially, in the cooking liquor may be a bio-based non-paper material. Bio-based materials are materials composed in whole or in significant part of biological products. Suitable bio-based non-paper material 12 may include, for example, starch.

The non-paper material 12 may take the form of various contaminants within the feedstock paper 11. In an aspect, the non-paper material 12 capable of dissolving, at least partially, in the cooking liquor may take the form of packaging material, such as adhesive, adhesive tapes, air pillows, bubble wrap, cold packs, packaging foam, packaging peanuts, plastic wrap, printing labels, RFID tags, or any other material employed in the packaging of a product for shipping. The non-paper material 12 may serve a variety of functions. The non-paper material 12 capable of dissolving, at least partially, in the cooking liquor may include paper material that does not dissolve in the cooking liquor.

First exemplary non-paper material 12 in the form of packaging material may serve the function of bonding a package together. The non-paper material 12 in the form of packaging material may be bonded between two opposing faces of feedstock papers. In an example, first exemplary non-paper material in the form of packaging material may include adhesive capable of dissolving, at least partially, in the cooking liquor. In another example, first exemplary non-paper material in the form of packaging material may include adhesive tapes (e.g., standard or fiber-reinforced) capable of dissolving, at least partially, in the cooking liquor.

Second exemplary non-paper material 12 may serve the function of sealing a package. The non-paper material 12 in the form of packaging material may be sealing between two opposing ends of feedstock papers. In an example, second exemplary non-paper material 12 in the form of packaging material may include adhesive tapes (e.g., standard or fiber-reinforced) capable of dissolving, at least partially, in the cooking liquor.

Third exemplary non-paper material 12 in the form of packaging material may serve the function of adhering to the outside or inside the package, such as for identification purposes. The non-paper material 12 in the form of packaging material may be adhered to a surface of a feedstock paper. In an example, third exemplary non-paper material 12 in the form of packaging material may include printing labels capable of dissolving, at least partially, in the cooking liquor. In another example, third exemplary non-paper material 12 in the form of packaging material may include RFID tags capable of dissolving, at least partially, in the cooking liquor.

Fourth exemplary non-paper material 12 in the form of packaging material may serve the function of protecting a product contained within the package. The non-paper material 12 in the form of packaging material may be unattached to any feedstock paper. In an example, fourth exemplary non-paper material 12 in the form of packaging material may include air pillows capable of dissolving, at least partially, in the cooking liquor. In another example, fourth exemplary non-paper material 12 in the form of packaging material may include cold packs capable of dissolving, at least partially, in the cooking liquor. In yet another example, fourth exemplary non-paper material 12 in the form of packaging material may include packaging foam capable of dissolving, at least partially, in the cooking liquor. In yet another example, fourth exemplary non-paper material 12 in the form of packaging material may include packaging peanuts capable of dissolving, at least partially, in the cooking liquor. In yet another example, fourth exemplary non-paper material 12 in the form of packaging material may include plastic wrap capable of dissolving, at least partially, in the cooking liquor.

For example, in the case of a feedstock paper 11 that is (or includes) OCC materials, the feedstock paper 11 may contain various contaminates, such as adhesive, adhesive tapes (e.g., standard or fiber-reinforced), air pillows, bubble wrap, cold packs, packaging foam, packaging peanuts, plastic wrap, printing labels, RFID tags, and other non-paper packaging materials. In the feedstock 10 of the present disclosure, non-paper material 12 (e.g., contaminants) is formed from non-paper material 12 capable of dissolving, at least partially, in the cooking liquor. Thus, because the non-paper material 12 included with the feedstock paper 11 is capable of dissolving, at least partially, in the cooking liquor, the feedstock 10 of the present disclosure may be utilized in the methods of the present disclosure without necessitating separation of non-paper material 12 prior to conversion of the feedstock paper 11 into bleached recycled pulp.

The non-paper material 12 capable of dissolving, at least partially, in the cooking liquor may include paper material that does not dissolve in the cooking liquor, but the paper material within the non-paper material 12 may be repulped with the feedstock papers. In an example, a fiber-reinforced adhesive tapes may include cellulosic fibers that reinforce the adhesive tape. The cellulosic fibers may not dissolve in the cooking liquor. However, the cellulosic fibers may be pulped to manufacture the recycled bleached pulp. In another example, a printing label may include paper material and non-paper material 12 capable of dissolving, at least partially, in the cooking liquor. The paper material may not dissolve in the cooking liquor. However, the paper material may be pulped to manufacture the recycled bleached pulp.

The feedstock 10 of the present disclosure excludes substantial amounts of other solid materials that do not dissolve in the cooking liquor. In one implementation, at least 90 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. In another implementation, at least 95 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. In yet another implementation, at least 98 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. In yet another implementation, at least 99 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. In yet another implementation, at least 99.5 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. In yet another implementation, at least 99.8 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. In yet another implementation, at least 99.9 weight percent of the solids content of the feedstock 10 is the feedstock paper 11 and the non-paper material 12. By limiting the amounts of solid materials that do not dissolve in the cooking liquor, separation of the non-dissolved solid materials can be minimized or avoided.

The feedstock 10 may contain water. The quantity of water in the feedstock may be due to the equilibrium moisture content or may be greater than the equilibrium moisture content. In one expression, the feedstock may have a solids content of at least 70 percent by weight. In another expression, the feedstock may have a solids content of at least 75 percent by weight. In another expression, the feedstock may have a solids content of at least 80 percent by weight. In another expression, the feedstock may have a solids content of at least 85 percent by weight. In another expression, the feedstock may have a solids content of at least 90 percent by weight. In yet another expression, the feedstock may have a solids content of at least 95 percent by weight.

The feedstock 10 may be in the form of a bundle of feedstock paper 11 and non-paper material 12 pressed together into a densified mass. Various types of feedstock paper 11 may be used without departing from the scope of the present disclosure. In one specific example, a suitable feedstock paper 11 may be (or may include) old corrugated containers (OCC), which may be received in bulk (e.g., bales). An OCC bale is a bundle of old corrugated containers that have been pressed together at a high pressure into densified mass. A typical bale size may be, for example, in a range of from 5 to 100 cubic feet, such as in a range of from 10 to 50 cubic feet. Those skilled in the art will appreciate that a feedstock comprised of a mixture of different types of feedstock paper 11 may be used. Other non-limiting examples of suitable feedstock for the disclosed methods include corrugated box plant clippings, kraft bagging, newsprint, and recovered kraft fibers, double liner kraft (DLK), and paper mill broke (trim rolls or rejected quality rolls).

Illustrated in FIG. 1 is an example of the methods of the present disclosure, generally designated 100, for manufacturing bleached pulp 50 from a feedstock 10 comprising at least feedstock paper 11 and non-paper material 12.

At Block 110, the method 100 may include a step of reducing a size of the feedstock 10. The size reduction step (Block 110) may be performed before an impregnation step (Block 120), though variations are contemplated and will not result in a departure from the scope of the present disclosure.

Various techniques may be used for reducing the size of (e.g., shredding) the feedstock 10. As one non-limiting example, a hogger may be used to perform the size reduction step (Block 110). As another non-limiting example, a cutter may be used to perform the size reduction step (Block 110). As yet another non-limiting example, a slicer may be used to perform the size reduction step (Block 110).

At Block 120, the method 100 may include a step of impregnating the feedstock 10 with cooking liquor 20 prior to a cooking step (Block 130). In one particular implementation, the cooking liquor 20 may be a kraft cooking liquor, and may include sodium hydroxide (NaOH) and sodium sulfide (Na₂S) among other possible components. In other particular implementations, the cooking liquor 20 may use other types of cooking chemistries (soda, sulfite, green liquor, and carbonate).

The impregnation step (Block 120) may yield an impregnated material 22 having a liquor-to-fiber mass ratio. In one expression, the liquor-to-fiber mass ratio may be at most about 4:1. In another expression, the liquor-to-fiber mass ratio may be at most about 3:1. In another expression, the liquor-to-fiber mass ratio may be less than 3:1. In another expression, the liquor-to-fiber mass ratio may be at most about 2.5:1. In another expression, the liquor-to-fiber mass ratio may be at most about 2:1. In yet another expression, the liquor-to-fiber mass ratio may range from about 1:1 to about 3:1. Because of the relatively low liquor-to-fiber mass ratio of the impregnated material 22, those skilled in the art will appreciate that the subsequent cooking step (Block 130) may be referred to as vapor-phase digestion. However, the present disclosure is not limited to a low liquor-to-fiber mass ratio or to vapor-phase digestion.

The cooking liquor 20 used in the impregnation step (Block 120) may contain a percentage of active alkali ions. In one expression, the percentage of active alkali ions may be about 5 percent by weight of the feedstock 10 to about 10 percent by weight of the feedstock 10. In another expression, the percentage of active alkali ions may be about 5 percent by weight of the feedstock to about 15 percent by weight of the feedstock. In another expression, the percentage of active alkali ions may be about 5 percent by weight of the feedstock to about 20 percent by weight of the feedstock. In yet another expression, the percentage of active alkali ions may be about 5 percent by weight of the feedstock to about 25 percent by weight of the feedstock.

As shown in Block 122, the impregnation step (Block 120) may include the step of compressing the feedstock 10. Without being limited to any particular theory, it is believed that compressing the feedstock 10 aids in the impregnation step (Block 120) and facilitates a more uniform distribution of the cooking liquor 20 throughout the impregnated material 22.

Various techniques may be used to perform the compressing step (Block 122). As one specific, non-limiting example, the compressing step (Block 122) may be performed by a plug/compression screw feeder, such as an MSD Impressafiner®, which is commercially available from Andritz AG of Graz, Austria. As another non-limiting example, the compressing step (Block 122) may be performed by a screw press. As yet another non-limiting example, the compressing step (Block 122) may be performed by a kneader. The use of multiple different apparatus (e.g., in series and/or in parallel) for performing the compressing step (Block 122) is also contemplated.

The compressing step (Block 122) may be performed on the feedstock 10 to achieve a desired compression ratio. In one expression, the compressing step (Block 122) may be performed to achieve a compression ratio greater than 1:1, on a volume basis. In another expression, the compressing step (Block 122) may be performed to achieve a compression ratio of at least about 1.5:1, on a volume basis. In another expression, the compressing step (Block 122) may be performed to achieve a compression ratio of at least about 2:1, on a volume basis. In another expression, the compressing step (Block 122) may be performed to achieve a compression ratio of at least about 2.5:1, on a volume basis. In another expression, the compressing step (Block 122) may be performed to achieve a compression ratio of at least about 3:1, on a volume basis. In another expression, the compressing step (Block 122) may be performed to achieve a compression ratio of at least about 3.5:1, on a volume basis. In another expression, the compressing step (Block 122) may be performed to achieve a compression ratio of at least about 4:1, on a volume basis. In yet another expression, the compressing step (Block 122) may be performed to achieve a compression ratio between about 2:1 and about 4:1, on a volume basis.

As shown in Block 124, the impregnation step (Block 120) may further include the step of adding a surfactant to the feedstock 10. Without being limited to any particular theory, the addition of surfactant may aid in the penetration of cooking liquor 20 into materials.

At Block 130, the method 100 includes the step of cooking the impregnated material 22 to dissolve lignin 13 from the feedstock paper 11 and to dissolve, at least partially, the non-paper material 12 into the cooking liquor 20, thereby yielding a cooked pulp 24. The cooking step (Block 130) may be performed in a continuous digester, such as a Pandia-type digester, a Messig & Durkee (M&D-type) digester, a Kamyr-type digester, or the like. However, the use of a batch digester (or both a batch digester and a continuous digester) is also contemplated.

The cooking step (Block 130) dissolves lignin 13 from the feedstock paper 11 into the cooking liquor 20. In one expression, the cooking step (Block 130) may be performed to a kappa number of at most about 40. In another expression, the cooking step (Block 130) may be performed to a kappa number of at most about 35. In another expression, the cooking step (Block 130) may be performed to a kappa number of at most about 33. In another expression, the cooking step (Block 130) may be performed to a kappa number of at most about 30. In yet another expression, the cooking step (Block 130) may be performed to a kappa number ranging from about 15 to about 40. In yet another expression, the cooking step (Block 130) may be performed to a kappa number ranging from about 24 to about 32.

The cooking step (Block 130) may be performed at a cooking temperature and the impregnated material 22 may have a residence time at the cooking temperature. Those skilled in the art will appreciate that the cooking temperature and the residence time may depend on various factors, such as the chemistry of the cooking liquor 20 and the liquor-to-fiber mass ratio of the impregnated material 22. For example, when the cooking liquor 20 is a kraft cooking liquor, the cooking temperature may range from about 140° C. and about 170° C., and the residence time may range from about 30 minutes to about 90 minutes at the cooking temperature.

During the step of cooking the impregnated material 22, the non-paper material 12 dissolve, at least partially, into the cooking liquor 20 at the same conditions during which the cooking step dissolves lignin 13 from the feedstock paper 11 into the cooking liquor 20. In one implementation, the non-paper material 12 dissolves into the cooking liquor 20 more easily than the lignin 13 from the feedstock paper 11 so that the non-paper material 12 is fully dissolved when the desired amount of lignin is removed from the feedstock paper 11.

At Block 135, the method 100 may include the step of screening the cooked pulp 24 to remove rejects 136. For example, the rejects 136 may include undissolved material 137, such as undissolved non-paper material 12. At this point, those skilled in the art will appreciate that the screening step 135 may only be required when the non-paper material 12 is not fully (about 100 percent) soluble in the cooking liquor 20.

At Block 140, the method 100 includes the step of washing the cooked pulp 24 to yield washed pulp 26 and spent cooking liquor 30. The washing step (Block 140) may be performed, for example, with water or an aqueous solution, as is well known in the art.

At Block 150, the spent cooking liquor 30 is regenerated to yield regenerated cooking liquor 20 using a positive heating value of the dissolved lignin and the dissolved non-cellulosic organic components in the spent cooking liquor 30. The regeneration step, block 150, is not limited and may include any method for regenerating a spent cooking liquor 30. For example, the step of regenerating the spent cooking liquor 30 may include, for example, an evaporation step at block 152 and a recovery step at block 154.

At Block 160, the method 100 may optionally include the step of blending the cooked pulp 24 (or washed pulp 26, if washed first) with virgin pulp 40 (i.e., pulp not obtained by recycling) to yield a pulp blend 42. The blending step (Block 160) may be performed prior to the bleaching step (Block 170), though variations (e.g., blending after bleaching) are also contemplated.

The pulp blend 42 may contain various quantities of virgin pulp 40 without departing from the scope of the present disclosure. In one non-limiting example, the pulp blend 42 includes about 5 percent by weight to about 95 percent by weight cooked pulp 24 (or washed pulp 26, if washed first), with balance virgin pulp 40. In another non-limiting example, the pulp blend 42 includes about 5 percent by weight to about 85 percent by weight cooked pulp 24 (or washed pulp 26, if washed first), with balance virgin pulp 40. In another non-limiting example, the pulp blend 42 includes about 5 percent by weight to about 75 percent by weight cooked pulp 24 (or washed pulp 26, if washed first), with balance virgin pulp 40. In another non-limiting example, the pulp blend 42 includes about 5 percent by weight to about 65 percent by weight cooked pulp 24 (or washed pulp 26, if washed first), with balance virgin pulp 40. In another non-limiting example, the pulp blend 42 includes about 5 percent by weight to about 50 percent by weight cooked pulp 24 (or washed pulp 26, if washed first), with balance virgin pulp 40. In yet another non-limiting example, the pulp blend 42 includes about 10 percent by weight to about 30 percent by weight cooked pulp 24 (or washed pulp 26, if washed first), with balance virgin pulp 40.

At Block 170, the method 100 includes the step of bleaching the cooked pulp 24 (or the washed pulp 26, if washed, or the pulp blend 42, if blended) to yield bleached pulp 50. The bleaching step (Block 170) increases the brightness of the pulp. In one expression, the bleaching step (Block 170) is performed to achieve a GE brightness of at least about 70 percent. In another expression, the bleaching step (Block 170) is performed to achieve a GE brightness of at least about 75 percent. In another expression, the bleaching step (Block 170) is performed to achieve a GE brightness of at least about 80 percent. In another expression, the bleaching step (Block 170) is performed to achieve a GE brightness of at least about 85 percent. In yet another expression, the bleaching step (Block 170) is performed to achieve a GE brightness of at least about 90 percent.

Various bleaching techniques may be used for the bleaching step (Block 170). As one non-limiting example, the bleaching step (Block 170) includes traditional chlorine bleaching. As another non-limiting example, the bleaching step (Block 170) includes chlorine dioxide bleaching. As another non-limiting example, the bleaching step (Block 170) includes peroxide bleaching. As another non-limiting example, the bleaching step (Block 170) includes oxygen bleaching.

At Block 180, the method 100 may include the step of storing the bleached pulp 50 in a storage vessel. For example, the storing step (Block 180) may include storing the bleached pulp in a high-density storage tank. After storing (or as an alternative to storing), the bleached pulp 50 may be used to manufacture various articles (e.g., paperboard; cups containing paperboard; etc.). Accordingly, the method 100 produces recycled bleached pulp 50, which may be used in a variety of applications, such as for manufacturing paper, including paperboard.

FIG. 2 is a schematic illustration of a packaging system according to an aspect of the present description, in an unsealed state. FIG. 3 is a schematic illustration of the packaging system of FIG. 2 in a sealed state.

The present disclosure relates to a novel packaging system 60 having improved sustainability. The packaging system 60 comprises a corrugated package 70 and a non-paper packaging material 80 capable of dissolving, at least partially, in a cooking liquor, which is a chemical solution employed to reduce wood chips (or, in the case of the present disclosure, feedstock paper) into cellulose fiber by dissolving lignin. In one particular implementation, the cooking liquor may be a kraft cooking liquor, and may include sodium hydroxide (NaOH) and sodium sulfide (Na₂S) among other possible components. In other particular implementations, the cooking liquor may use other types of cooking chemistries (soda, sulfite, green liquor, and carbonate).

The corrugated package 70 includes a plurality of corrugated walls 71 defining an opening 72 for placing or removing a product 90 therein. The opening 72 is in the unsealed state before placing the product 90 in the corrugated package 70. The opening 72 is in the sealed state after to placing the product 90 in the corrugated package 70 and during transportation of the corrugated package 70 to a destination. The opening 72 is in the unsealed state after removing the product 90 from the corrugated package 70. The form of the corrugated package 70 is not limited and may include, for example, a corrugated box formed from a single blank of corrugated paperboard, in which corrugated walls 71 are formed by folding the corrugated paperboard, and in which at least one of the walls includes overlapping portions of paperboard, between which are positioned an adhesive or adhesive tape.

The non-paper packaging material 80 capable of dissolving, at least partially, in a cooking liquor may serve a variety of functions with regards to the corrugated package 70.

A first exemplary non-paper packaging material 80 may serve the function of bonding the corrugated package 70 together. The first exemplary non-paper packaging material may be bonded between two opposing faces of the corrugated package. For example, the first exemplary non-paper packaging material may include adhesive or adhesive tapes (e.g., standard or fiber-reinforced) capable of dissolving, at least partially, in a cooking liquor.

A second exemplary non-paper packaging material may serve the function of sealing the corrugated package 70. The non-paper packaging material may be sealing between two opposing ends of the corrugated package 70. For example, the second exemplary non-paper packaging material may include adhesive or adhesive tapes (e.g., standard or fiber-reinforced) capable of dissolving, at least partially, in a cooking liquor.

A third exemplary non-paper packaging material 80 may serve the function of adhering to the outside or inside the corrugated package 70, such as for identification purposes. The non-paper packaging material may be adhered to a surface of a corrugated package 70. In an example, the third exemplary non-paper packaging material 80 may include a printing label capable of dissolving, at least partially, in a cooking liquor adhered to the outside or inside the corrugated package 70. In another example, the third exemplary non-paper packaging material include RFID tag capable of dissolving, at least partially, in a cooking liquor. The RFID tag may be adhered to the outside or inside the corrugated package 70.

A fourth exemplary non-paper packaging material 80 may serve the function of protecting a product 90 contained within the corrugated package 70. The non-paper packaging material 80 may be unattached to any feedstock paper. For example, the fourth exemplary non-paper packaging material include non-paper packaging material capable of dissolving, at least partially, in a cooking liquor contained within the corrugated package 70, such as air pillows capable of dissolving, at least partially, in a cooking liquor, bubble wrap capable of dissolving, at least partially, in a cooking liquor, cold packs capable of dissolving, at least partially, in a cooking liquor, packaging foam capable of dissolving, at least partially, in a cooking liquor, packaging peanuts capable of dissolving, at least partially, in a cooking liquor, and plastic wrap capable of dissolving, at least partially, in a cooking liquor. In another example, the fourth exemplary non-paper packaging material may include a paper packing material contained within the corrugated package 70, to which an adhesive or adhesive tapes (e.g., standard or fiber-reinforced) is adhered thereto, in which the adhesive or adhesive tape is capable of dissolving, at least partially, in a cooking liquor.

The corrugated package 70 includes lignin and cellulose. The corrugated package 70 may have a relatively high quantity of lignin. In one expression, the corrugated package 70 may have a kappa number of at least 60. In another expression, the corrugated package 70 useful in the disclosed methods may have a kappa number of at least 70. In another expression, the corrugated package 70 useful in the disclosed methods may have a kappa number of at least 80. In another expression, the corrugated package 70 useful in the disclosed methods may have a kappa number of at least 90. In yet another expression, the corrugated package 70 useful in the disclosed methods may have a kappa number of at least 100. In yet another expression, the corrugated package 70 useful in the disclosed methods may have a kappa number of at least 110. In yet another expression, the corrugated package 70 useful in the disclosed methods may have a kappa number of at least 120.

The non-paper packaging material 80 include any non-paper material capable of dissolving, at least partially, in a cooking liquor, which is a chemical solution employed to reduce wood chips (or, in the case of the present disclosure, feedstock paper) into cellulose fiber by dissolving lignin. In one particular implementation, the cooking liquor may be a kraft cooking liquor, and may include sodium hydroxide (NaOH) and sodium sulfide (Na₂S) among other possible components. In other particular implementations, the cooking liquor may use other types of cooking chemistries (soda, sulfite, green liquor, and carbonate).

In one particular aspect, the non-paper packaging material 80 have a positive gross heating value in the dissolved state when dissolved within the cooking liquor. By having a positive heating value in the dissolved state when dissolved within the cooking liquor, the non-paper packaging material 80 contribute to a regeneration process for regenerating a spent cooking liquor to yield regenerated cooking liquor using the positive heating value of the non-paper packaging material 80. The heating value in the dissolved state may be determined by comparing a heating value of a spent cooking liquor with the dissolved non-paper packaging material 80 with a heating value of a spent cooking liquor without the dissolved non-paper packaging material 80. If the heating value of the spent cooking liquor with the dissolved non-paper packaging material 80 is greater than the heating value of a spent cooking liquor without the dissolved non-paper packaging material 80, then the non-paper packaging material 80 has a positive gross heating value in the dissolved state when dissolved within the cooking liquor. In one implementation, the non-paper packaging material 80 has a high positive gross heating value in the dissolved state when dissolved within the cooking liquor. In one example, the non-paper packaging material 80 may increase the heating value of the spent cooking liquor by at least 0.01 kJ per gram of the solid content of the non-paper packaging material 80. In another example, the non-paper packaging material 80 may increase the heating value of the spent cooking liquor by at least 0.1 kJ/g. In another example, the non-paper packaging material 80 may increase the heating value of the spent cooking liquor by at least 1 kJ/g. In yet another example, the non-paper packaging material 80 may increase the heating value of the spent cooking liquor by at least 10 kJ/g.

Exemplary suitable non-paper packaging material 80 include organic or inorganic non-paper material 12 capable of dissolving, at least partially, in the cooking liquor. Suitable non-paper material may include, for example, acrylic, ethylene vinyl acetate, epoxy resins, fiberglass, isocyanate, isoprene, polyethylene glycol, polyethylene oxide, polyvinyl acetate, polyvinyl chloride, propionates, silicone, starch, stearic acid monoglycerides, and styrene acrylic.

In one particular implementation, the non-paper packaging material 80 capable of dissolving, at least partially, in the cooking liquor may be a bio-based non-paper material. Bio-based materials are materials comprises in whole or significant part of biological products. Suitable bio-based non-paper material may include, for example, starch.

The non-paper packaging material 80 may include paper material that does not dissolve in the cooking liquor, but the paper material within the non-paper packaging material 80 may be repulped. In an example, a fiber-reinforced adhesive tapes may include cellulosic fibers that reinforce the adhesive tape. The cellulosic fibers may not dissolve in the cooking liquor. However, the cellulosic fibers may be pulped to manufacture the recycled bleached pulp. In another example, a printing label may include paper material and non-paper material capable of dissolving in the cooking liquor. The paper material may not dissolve in the cooking liquor. However, the paper material may be repulped to manufacture the recycled bleached pulp.

After utilization of the corrugated package 70 and the non-paper packaging material 80, they may be utilized as feedstock 10 for the method 100 of the present description.

EXAMPLE 1

In this example two components from a novel packaging system 60 shown in FIG. 3 were separated into their individual component forms (i.e., corrugated package 70 and a non-paper packaging material 80) to enable measurement of the residual cooking liquor heating values as a result of alkali digestion. Combined box board packaging as the corrugated package 70 was collected from recycled materials made from traditional linerboard, corrugating medium and starch-based adhesives. The non-paper packaging material 80 was a tape available from 3M as Product R3187. Both components were dry shredded independently for the purpose of the experiment.

After shredding, each component listed above was digested independently in small laboratory digester reactors at typical kraft pulping conditions using a kraft white liquor mixture of sodium hydroxide and sodium sulfide as the cooking liquor portrayed as 20 in FIG. 1. An 18% alkali charge as active alkali on dry combined board or dry tape was used at 25% sulfidity and cooked to a temperature of 165 degrees centigrade and held at this temperature for about 30 to 35 minutes for each cook. After the cook time was completed, for both cooks, the digester was cooled, and contents removed and washed in the laboratory on a Buchner funnel with clean wash water. From FIG. 1, the remaining separated fiber suspended solids (washed pulp 26) and spent cooking liquor 30 (with dissolved lignin 13) were separated from the Buchner funnel. The washed pulp 26 can be further processed into unbleached paper or subjected to further processing to produce a bleached pulp 50. The cooking liquor 30 was further evaporated and tested for higher heating values on a moisture free dry basis.

Table 1 demonstrates the contribution of the packaging material before digestion, the resulting digested pulp, and residual cooking black liquors to the higher heating value on a KJ per oven dried gram solids basis or on a moisture free basis. The as-is columns represent the components total higher heating value on a bone-dry basis before digestion, while the pulp and black liquor columns represent the two component streams after the alkali digestion and the washing separation phase completed. Higher heating values on a fuel solids dry basis were determined on an IKA calorimeter C 6000 Isoperibol and the TAPPI method T684 was used to determine the heating values of the black liquors.

Under similar cooking conditions and white liquor charges the tape component process black liquors contributed about 7% more KJ/g on the dry solids recovered over the recovered combined board, 7.7 KJ/g versus 7.2KJ/g. These results represent higher heating values and include extracted lignin from the fibrous components of each and the dry inorganic cooking liquor solids of the cooking chemicals, and adhesives from the tape. The adhesives and non-fibrous materials of the packing tape broke down into the alkali cooking liquors and were successfully washed from the residual fiber of the tape backing. For recovered pulps of Table 1 a measure of residual lignin content made by the TAPPI standard T236 was made on the recovered fibers from both components. Kappa number of the combined board prior to digestion was about 82.3. The cooking process will both remove product lignin from the medium and linerboard grades, isolate the fiber from the tape backing, and dissolve the non-fibrous adhesive components into the process black liquors for improved heating value.

TABLE 1 Recycled Corrugated Board Recovered from the Package Tape from the Package Item 70 Item 80 Control Control Tape Sample Control Black Tape Tape Black As-is Pulp Liquor As-is Pulp Liquor Higher Heating 16.2 15.9 7.2 20.5 17.4 7.7 Value (KJ/g) Kappa Number 19.30 16.70

Normal commercial operation and practice of this invention, the components would be received post-consumer with tape and labels still attached to the combined board package, dry shredded together and digested together eliminating several steps of the traditional package recycling effort. Typical non repulpable tapes would be replaced with the alkali soluble tapes while reclaiming the adhesives to utilize as fuel value in a traditional kraft recovery system. After digestion, these recovered residual black residual cooking liquors are concentrated and energy captured through combustion, while any cellulosic components of 70 and 80 are recovered can be used as is or further bleached and used for future packaging. This example provides evidence that a positive gain in process cooking liquor heating values is possible if the packaging materials of the present description are co digested with the combined board.

Although various embodiments of the disclosed methods, feedstock, and packaging systems have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims. 

1. A method for manufacturing bleached pulp from a feedstock comprising feedstock paper and non-paper material, the feedstock paper comprising lignin and cellulose, the method comprising: cooking the feedstock in a cooking liquor to dissolve at least a portion of the lignin from the feedstock paper and to at least partially dissolve the non-paper material in the cooking liquor, thereby yielding a cooked pulp; washing the cooked pulp to yield washed pulp and spent cooking liquor; regenerating the spent cooking liquor to yield regenerated cooking liquor; and bleaching the washed pulp.
 2. (canceled)
 3. The method of claim 1, wherein the feedstock paper has, on average, a kappa number of at least
 70. 4. (canceled)
 5. The method of claim 1, wherein the feedstock paper has, on average, a kappa number of at least
 90. 6. (canceled)
 7. The method of claim 1, wherein the feedstock paper has, on average, a kappa number of at least
 110. 8. The method of claim 1, wherein the feedstock paper has, on average, a kappa number of at least
 120. 9. The method of claim 1, wherein the feedstock paper includes OCC materials.
 10. The method of claim 1, wherein the non-paper material has a positive gross heating value in a dissolved state within the cooking liquor.
 11. (canceled)
 12. The method of claim 1, wherein the non-paper material has a positive gross heating value in a dissolved state within the cooking liquor of at least 0.1 kJ per gram of a solid content of the non-paper material.
 13. (canceled)
 14. The method of claim 1, wherein the non-paper material has a positive gross heating value in a dissolved state within the cooking liquor of at least 10 kJ per gram of a solid content of the non-paper material.
 15. The method of claim 1, wherein the non-paper material comprises organic non-paper material.
 16. The method of claim 1, wherein the non-paper material comprises inorganic non-paper material.
 17. The method of claim 1, wherein the non-paper material comprises non-paper packaging material.
 18. The method of claim 1, wherein the non-paper material comprises non-paper packaging material bonded between two opposing faces of feedstock papers.
 19. The method of claim 1, wherein the non-paper material comprises non-paper packaging material sealing between two opposing ends of feedstock papers.
 20. The method of claim 1, wherein the non-paper material comprises non-paper packaging material adhered to a surface of a feedstock paper.
 21. The method of claim 1, wherein the non-paper material comprises non-paper packaging material unattached to any feedstock paper.
 22. The method of claim 1, wherein the non-paper material comprises adhesive.
 23. The method of claim 1, wherein the non-paper material comprises adhesive tape. 24-31. (canceled)
 32. The method of claim 1, wherein the step of cooking the feedstock in cooking liquor is cooking the feedstock in kraft cooking liquor.
 33. The method of claim 1, wherein the step of regenerating the spent cooking liquor to yield regenerated cooking liquor utilizes a positive gross heating value of the dissolved lignin and the dissolved non-paper material.
 34. The method of claim 1, whereby separation of the non-paper material from the feedstock paper is avoided prior to the cooking of the feedstock in cooking liquor, thereby avoiding a traditional OCC plant to prep the fiber for cooking.
 35. The method of claim 1, wherein the cooking comprises cooking the feedstock in the cooking liquor to substantially fully dissolve the non-paper material in the cooking liquor.
 36. (canceled)
 37. The method of claim 1, wherein the non-paper material is at least 90 percent (by weight) soluble in the cooking liquor. 38-39. (canceled)
 40. A feedstock for manufacturing bleached pulp, the feedstock comprising: feedstock paper; and non-paper material intermixed with the feedstock paper, wherein the non-paper material is capable of at least partially dissolving in a cooking liquor. 41-72. (canceled)
 73. A packaging system comprising: a corrugated package; and a non-paper packaging material capable of at least partially dissolving in a cooking liquor. 74-103. (canceled) 